Channel estimation based on the fixed DVB-S2 system to transfer images

By dividing the available spectrum into multiple bands, multi-band ultra-wideband (UWB) systems possess many advantages, such as the flexibility to eliminate possible interference and coexistence problems with available wireless standards. UWB channels have large delay spread, causing inter- symbol interference (ISI) in high rate systems. The RAKE receiver is often used to capture multipath energy, but it is incapable of ISI compensation, causing severe bit error rate (BER) degradation in practical UWB channels. This paper proposes an over-sampling multi-channel equalizer per sub-band for multi-band UWB. The performance of the proposed receiver is compared with the RAKE receiver through analytical and simulation studies. The proposed equalizer has been shown to be able to handle ISI under any channel conditions or data rate presented, with an acceptable BER. In addition, the rich multipath diversity of the UWB channels is harnessed by the over-sampling scheme, for output SNR improvement. one. Therefore, equalization receiver based on adaptive algorithms seems to be an effective way to recover the transmitted data. With this consideration, we propose an over-sampling multi-channel equalizer per sub-band for a multi-band UWB system, which provides more effective inter-symbol interference (ISI) suppression compared with the conventional RAKE receiver when operating in channels with large delay spread. Through detailed theoretical analysis and extensive simulations, we are able to show that the proposed 4-arm equalizer scheme is superior to a 4-arm conventional RAKE receiver in the presence of ISI at all signal-to-noise ratios (SNRs). Based on the method presented in (4), the simulated performance is shown to conform to analytical predictions. The RAKE receiver is incapable of ISI compensation, and a moderate level of ISI is shown to cause severe bit error rate (BER) degradation. The proposed over-sampling equalizer, on the other hand, is able to handle ISI under any channel conditions or data rate, with an acceptable BER. Over- sampling is shown to be able to achieve diversity gain, and improves the output SNR.

Wavelet transform-based methodologies for both Automatic Modulation Recognition (AMR) and Demodulation of digitally modulated communications signals can be utilized in an enabling platform for the implementation of a new class of communications systems. In particular, such techniques could enable the development of agile radio transceivers for use in both commercial and military applications. Such radio transceivers would have the ability to transmit and receive signals using many different modulation schemes while employing a common receiver architecture based on a single demodulator. In this dissertation, the development of AMR and Demodulation techniques are based on the relatively new mathematical theory of Wavelet Transforms (WTs). Information-bearing signals acquired by communications receivers are transformed into the wavelet-domain using the Continuous Wavelet Transform (CWT) and then applied to signal processing algorithms that also use the CWT in conjunction with pattern recognition techniques. In particular, the method of template-matching is used for both the AMR and Demodulation processes. Signal templates characterizing various modulated signals are used for both processes. The signal templates are determined based on the signal features present in the fractal patterns of their corresponding scalograms for specific modulation schemes as they appear in the wavelet-domain. The algorithms developed in this work are capable of both classifying the method of modulation used in the acquired signal, as well as subsequently automatically demodulating the signal to recover the message. The classes of digitally modulated signals considered in this work include variants of the Amplitude-, Frequency-, Phase-Shift Keying modulation families, i.e., ASK, FSK, and PSK, respectively, and multiple-level Quadrature Amplitude Modulation (M-ary QAM) families. The AMR and Demodulation performances are evaluated in the presence of Additive White Gaussian Noise (AWGN) over a wide range of Signal-to-Noise Ratio (SNR) values. Through extensive Monte Carlo computer simulations it is determined that the average correct classification rates using wavelet-based AMR for PSK, ASK, and QAM are over 98%, and over 90% for FSK signals, all at an SNR of 0 dB. The Bit Error Rate (BER) performance obtained using wavelet-based Demodulation is at least one order of magnitude better than the matched filter-based BER performance realized for the modulation schemes considered.

The increasing demand for high-density and high-speed digital optical recording systems has made the development of advanced coding and signal processing techniques for fast and reliable data recovery increasingly important. In recent years, the parity-check (PC)-code-based reception technique has been widely studied for magnetic recording systems, and it is projected to be highly promising for high-density optical recording. The PC code is an inner error correction code (ECC), which can detect dominant short error events of the system, using only a few parity bits. This reduces the loss in error correction capability of the outer ECC due to random short errors and results in a simple and efficient solution to improve the overall performance. This thesis is dedicated to the design and analysis of PCcode- based recording systems to achieve higher recording capacity with low implementation complexity, for high-density blue laser disc systems. In particular, most of the key components of the PC-code-based optical recording system have been designed and optimized for different recording densities, and different proportions of white noise and media noise. During the development of advanced coding and detection techniques, it becomes necessary to investigate the system’s performance with different coding schemes and recording densities. In Chapter 2 of the thesis, we propose a generalized Braat-Hopkins model for optical recording channels, which provides a fair basis for the performance comparison of detection schemes over different coding schemes and recording densities, for channels with additive, white Gaussian noise (AWGN) and media noise. Various basic issues associated with the PC-code-based systems are investigated in Chapter 3. These include bounds for bit error rates and error event probabilities, the dominant error events at channel detector output, different PC codes, simple and efficient post-processors, the impact of error events that are split across data block boundaries and the corresponding remedy, as well as the effects of code rates and recording densities. Simulation results show that a 4-bit PC code achieves the best performance. The corresponding bit error rates (BERs) are very close to the performance bounds, at both nominal and high densities. Constrained codes, which serve as a key component in the read-write channel of data storage systems, are desired to have a high code rate with low-complexity encoder/decoder. In Chapter 4, we investigate the design of certain capacity-approaching constrained codes for optical recording systems. In particular, we derive analytically the relationship between the number of encoder states and the maximum size of these codes. We identify the minimum number of encoder states that maximizes the code rate, for any desired codeword length. The design of constrained PC codes is key to the development of PCcode- based systems, and the systematic design of efficient constrained PC codes remains a challenging problem. In Chapter 5, we propose a general and systematic code design technique for constructing capacity-approaching constrained PC codes, which can detect any type of error events of the system, with the minimum code rate loss. Compared to the rate 2/3 code without parity, the newly designed constrained 4-bit PC code achieves a performance gain of 2 dB at nominal density, and 1.5 dB at high density, at BER = 10-5. As the dominant noise for high-density optical recording systems, media noise severely degrades the performance of channel detectors and postprocessors that are designed for AWGN. In Chapter 6, we propose two novel modifications to the bit detector to combat media noise. We further develop a data-dependent post-processing scheme for error correction. Compared to the system designed without considering media noise and without PC codes, the overall performance gain of the developed scheme can be more than 11 dB at high media noise levels. In data storage systems, the ECC failure rate (EFR) serves as the ultimate measure of the data recovery performance. In Chapter 7, we develop semi-analytical approaches for estimating the EFR, and analyze EFRs for the developed PC-code-based systems, for the cases without and with interleaving. Our analysis shows that with the optimum interleaving degrees, compared to the rate 9/13 code without parity, the 2-bit PC code achieves a gain of around 0.5 dB, and the 4-bit PC code gains 0.6 dB, at high record ing density and EFR = 10-16. The thesis concludes in Chapter 8 with some suggestions for further work.

This paper presents analytical results of the effects of jitter and inter symbol interference (ISI) on a millimeter-wave impulse radio (IR) transceiver, compared with performance of the developed 10-Gb/s W-band IR transmitter prototype. The compact and cost-effective IR transmitter consists of a pulse generator (PG) that creates a short pulse with a duration of <10 ps, a band-pass filter (BPF) that shapes the short pulse to the desired millimeter-wave pulse (wavelet), and a power amplifier (PA) which is deployed as an option. Jitters of the PG and ISI from the BPF are a great issue to make the IR transceiver robust and to obtain excellent performance. One analysis verified that, thanks to a novel retiming architecture, the random jitter and the data dependent jitter from the PG give only a small penalty of <0.5-dB increase in signal to noise ratio (SNR) for achieving a bit error rate (BER) of <10−12. The alternative analysis on the effect of ISI from the BPF indicated that using a Gaussian BPF enables transmission with a BER of <10−12 up to a data rate of 1.4 times as large as a bandwidth of the BPF, whereas the ISI analysis suggested that mismatching of the skirt characteristics of the developed BPF to those of a Gaussian BPF causes tail lobes following the wavelet, resulting in an on/off ratio of <15 dB and hence an SNR penalty of <6 dB.

In the study of measures to improve channel efficiency, we developed and presented a performance analysis of a digital communication system for image transmission in a multipath channel with fading, in the MATLAB/Simulink environment, one of the main advan tages being that it provides high interference immunity in the presence of noise and interference and signal delays. The scheme has been investigated for bit error rate (BER) on additive white Gaussian noise (AWGN) channel and multipath Rice and Rayleigh fading channel operating under the influence of inter-symbol interference (hereinafter ISI) and different parameters for the channel, where we considered cases of signal delay similar for EPA (extended pedestrian a model (EPA) standards). In this paper, we estimate the effectiveness of compensation for signal distortion in radio channels with fading on the basis coded orthogonal frequency-division multiplexing (COFDM) technology, an adaptive equalizer, amplifiers on the transmitter side and a normalizer on t he receiver side, which is an acute problem in the field of wireless communication. This system can be applied to transmit better quality high-resolution radiological images over a wireless network inside a building and for a model analogous of pedestrian traffic.

In this paper, we analyze the bit error rate (BER) performance of synchronous optical code division multiple access (OCDMA) system using an optical zero-correlation zone (ZCZ) sequence set over diffuse link by computer simulation, and evaluate the influence of inter-symbol interference (ISI) on the system. The optical ZCZ sequence set is a set of pairs of binary and bi-phase sequences with zero-correlation zone. As a result, the ISI can suppress by extension of zero-correlation zone.

Prior research studies have shown that the peak signal to noise ratio (PSNR) is the most frequent watermarked image quality metric that is used for determining the levels of strength and weakness of watermarking algorithms. Conversely, normalised cross correlation (NCC) is the most common metric used after attacks were applied to a watermarked image to verify the strength of the algorithm used. Many researchers have used these approaches to evaluate their algorithms. These strategies have been used for a long time, however, which unfortunately limits the value of PSNR and NCC in reflecting the strength and weakness of the watermarking algorithms. This paper considers this issue to determine the threshold values of these two parameters in reflecting the amount of strength and weakness of the watermarking algorithms. We used our novel watermarking technique for embedding four watermarks in intermediate significant bits (ISB) of six image files one-by-one through replacing the image pixels with new pixels and, at the same time, keeping the new pixels very close to the original pixels. This approach gains an improved robustness based on the PSNR and NCC values that were gathered. A neural network model was built that uses the image quality metrics (PSNR and NCC) values obtained from the watermarking of six grey-scale images that use ISB as the desired output and that are trained for each watermarked image’s PSNR and NCC. The neural network predicts the watermarked image’s PSNR together with NCC after the attacks when a portion of the output of the same or different types of image quality metrics (PSNR and NCC) are obtained. The results indicate that the NCC metric fluctuates before the PSNR values deteriorate.

Provision of broadband communications services in High Altitude Platform Station (HAPS) is a new idea and worthy to be discussed. One is the application of OFDM transmission technique as a medium for digital modulation in HAPS. HAPS is a new technology in the telecommunications sector at an altitude of 18-50 km (the stratosphere) and used to serve the broadband wireless access (BWA) and other multimedia devices. HAPS technology has advantages that can cover the lack of terrestrial and satellite technology. Performance of OFDM transmission technique in which a HAPS channel Rician channel can be evaluated by looking at the effect of K-factor. K-factor is the dominant signal power ratio (Line Of Sight) with multipath signal power. In real conditions on the ground, the received power is a combination of the dominant signal power and multipath signal power. The increase in elevation angle between the HAPS platform with user terminals resulted in the increasing value of K-factor and the influence that affected the performance of OFDM systems multipath fading. Effect of K-factor can be identified by computer simulation. Effect of K-factor observed by looking at the value of Bit Error Rate (BER) on the system to the value of signal to noise ratio (SNR) by varying the bitrate and frequency doppler. The results showed that the increasing value of K-factor at the same bitrate the smaller the resulting BER. This shows the better performance of OFDM systems. Meanwhile, the OFDM system performance deteriorated over increasing Doppler frequency. This is because the increasing value of K-factor at the same Doppler frequency resulting more BER value. Keywords: HAPS, OFDM, K-factor, BER, bit rate, Doppler frequency.

High Peak-to-Average Power Ratio (PAPR) of the transmitted OFDM signal is a well-known major drawback of the Orthogonal Frequency-Division Multiplexing (OFDM), so the High-Power Amplifier (HPA) is therefore necessary to operate in its linear region, i.e. with large back-off between the operating input power and its saturation region, so introducing not only in-band distortion, but also the adjacent channel interference. Specifically with the Long-Term Evolution (LTE) systems downlink, some sort of PAPR reduction, such as e.g. clipping, must be utilized. Considering that in many practical situations, determining PAPR demands complex test equipment, such as e.g. Vector Signal Analyzer (VSA), which might not be available, in this paper, we develop a simple Bit-Error-Rate (BER) based model for the (residual) PAPR estimation, by applying link abstraction, i.e. considering the easy measurable BER degradation due to HPA non-linearity, as if it were the consequence of the according level of additive white Gaussian noise (AWGN) abstracting the HPA distortion, while considering high Signal-to-Noise Ratio (SNR) and long enough cyclic prefix (CP), thus neglecting (real) additive noise and time dispersion (i.e. multipath fading and the consequent inter-symbol interference). The analytical model is verified by the appropriate Monte-Carlo simulations.

The research that used digital image processing to detect glaucoma has been known as one of the popular methods. The beginning step of the research is to choose the best channel among red, green, or blue (RGB) so it can ease the glaucoma segmentation. In choosing the channel, it is important to analyze deeply the used retinal images. Choosing of best component can affect the accuracy of glaucoma diagnosis results. In this research, the most suitable component will be analyzed to detect glaucoma based on the visual, MSE (Mean Square Error) value, and PSNR (Peak Signal to Noise Ratio). In this research, we used 85 images of glaucoma from the DRISTHI-GS database and 101 normal images from the RIM-ONE database. From the visualization, it showed that the red component had high brightness level so it can differ the optic disc and other parts of retinal eyes. The green component still has vessel blood so it will make it more difficult to segment the images. Blue component results in very dark of retinal image. From MSE and PNSR values, it showed that the green component had the smallest MSE value while the blue component has the biggest MSE value. PSNR value was obtained from the green component. Both red and blue components had PSNR value which had a small difference. From these results, it can be concluded that the MSE and PSNR values do not guarantee visual results. So that for further research, it is expected that the MSE and PSNR values will be obtained from the part that we want to observe

Orthogonal Frequency Division Multiplexing (OFDM) is an extensively used transmission technique that enables feasible modulation and demodulation in communication systems.Channel Estimation (CE) is applied in channel conditions where time-varying features are essential.However, Inter-Symbol Interference (ISI) occurs in MOFDM and leads to inaccurate channel impulse response estimation due to multi-path propagation.Therefore, this research proposes a Rayleigh Distribution with Flower Pollination Algorithm (RDFPA) for pilot insertion in CE to reduce Normalized Mean Square Error (NMSE) in the OFDM system.Additionally, the RDFPA identifies optimal factors by exploring possible areas in the global search space with quick convergence.To encode and decode the signals, the Space-Time Block Code (STBC) is applied, which improves communication and enhances the signal's spatial diversity.The 16-quadrate Amplitude Modulation (16-QAM) is used for signal modulation and demodulation.The Additive White Gaussian Noise (AWGN) is applied to the transfer signal from the transmitter to the receiver.The Bit Error Rate (BER), NMSE, and Symbol Error Rate (SER) are used to evaluate the RDFPA performance in CE.The RDFPA achieved a lower NMSE of 0.510-1 for a Signal-to-Noise Ratio (SNR) of 10dB, which is better than the existing Tunicate Swarm Optimization (TSO).

The performance of encoded opportunistic transmission schemes in wireless channels affected by Rayleigh fading and additive white Gaussian noise (AWGN) is analyzed. In opportunistic transmission, the information is transmitted only when the fading amplitude is above a threshold. For this, the receiver with the knowledge of the channel state information notifies the instants the transmitter should transmit. Opportunistic systems with convolutional error correcting codes or with trellis coded modulation are analyzed in terms of closed-form bit error rate (BER) expressions. Nevertheless, the approach presented can be employed with any kind of error correcting codes. Hence, the performance of turbo codes is also presented in the simulations. Monte Carlo simulations verify the accuracy of the derived expressions and provide insights on the system performance. Performance results show that uncoded and encoded opportunistic systems are superior to uncoded and encoded ordinary systems (non-opportunistic), respectively. In particular, the BER curves of the opportunistic system decay exponentially when the signal-to-noise ratio (SNR) increases. On the other hand, BER curves for ordinary transmission decay linearly, where the slope is proportional to the diversity that depends on the error correcting code. Thus, opportunistic systems require less SNR to guarantee the same BER of ordinary transmission. The BER gain increases as the SNR increases. It is also observed that uncoded opportunistic systems are even superior to encoded ordinary ones. The results are validated guaranteeing the same spectral efficiency for all the scenarios. Finally, due to the exponential decay of the BER curves, coding gain expressions, used in ordinary systems over AWGN, can be used as approximations for opportunistic transmission in fading channels.

A novel COntent-Based Rate-Adaptation (COBRA) model is proposed to improve the quality of video transmission over multiple-input multiple-output (MIMO) system with channel state information feedback (CSI). The model captures relationships among the video content type, video sub-stream bit-rates, achievable peak signal-to-noise ratios (PSNR), and channel bit error rate (BER). COBRA facilitates joint selection of physical layer parameters and video sub-stream configuration. Unlike existing methods, the COBRA model offers an efficient way of balancing losses in PSNR due to channel errors and non-transmission of some enhancements layers in a sub-stream, with a judicious mechanism of selecting sub-stream configurations and communication parameters. Simulations show that COBRA maintains video quality at acceptable levels over wide range of low channel signal-to-noise ratio (SNR) values. It achieves the same video PSNR as obtained by the complete stream transmission at 10 dB higher channel SNR.

Wavelet is one method that can be used as a step to recognition an individual . Wavelet is used to perform an image feature extraction . In the process of image texture analysis , showed the value of the coefficients of a wavelet . The magnitude of the coefficients obtained using wavelet feature extraction is influenced by several factors . Besides affected by the type of wavelet used , is also influenced by the magnitude of the wavelet decomposition level of itself. In the wavelet is known as the wavelet energy retention , which means the number of retained energy after undergoing a process of decomposition and cutting coefficients . During the decomposition process , the calculation for texture analysis is often a constraint . In order for the current calculation lighter texture analysis , necessary to the process of cutting coefficients based on the retention factor of the wavelet coefficients . Based on these issues , created a program to analyze the influence of variations in the level of wavelet decomposition and coefficient of variation coefficient of cutting a cut on the image . The object of this final project is 30 iris image that has been converted into polar form presented . Having experienced the process of cutting coefficients , to prevent the image of the reverse transformation has a big difference to the original image , in this study was calculated Mean Square Error ( MSE), Peak Signal to Noise Ratio ( PSNR), and Euclidean distance to determine the level of similarity of image input and output images . The Highest values of Retention ​, MSE and the Euclidean distance is obtained at the level of decomposition of 1 and the lowest at the level of decomposition 6 . While the truncated coefficient and PSNR values ​​obtained at the highest level of decomposition of 6 and the lowest level of decomposition of 6 . The variation coefficient of pieces , value retention and highest PSNR obtained at koefsien piece 5 and the lowest coefficient of 50 pieces . While the coefficient value is truncated , MSE and the highest Euclidean distance is obtained at koefsien pieces 50 and the lowest coefficient of 5 pieces . Keywords: iris, texture analysis, Haar wavelet transform, MSE, PSNR, E uclidean distance

Channel coding is a fundamental procedure in wireless telecommunication systems and has a strong impact on the data transmission quality. This effect becomes more important when the transmission must be characterised by low latency and low bit error rate, as in the case of vehicle-to-everything (V2X) services. Thus, V2X services must use powerful and efficient coding schemes. In this paper, we thoroughly examine the performance of the most important channel coding schemes in V2X services. More specifically, the impact of use of 4th-Generation Long-Term Evolution (4G-LTE) turbo codes, 5th-Generation New Radio (5G-NR) polar codes and low-density parity-check codes (LDPC) in V2X communication systems is researched. For this purpose, we employ stochastic propagation models that simulate the cases of line of sight (LOS), non-line of sight (NLOS) and line of sight with vehicle blockage (NLOSv) communication. Different communication scenarios are investigated in urban and highway environments using the 3rd-Generation Partnership Project (3GPP) parameters for the stochastic models. Based on these propagation models, we investigate the performance of the communication channels in terms of bit error rate (BER) and frame error rate (FER) performance for different levels of signal to noise ratio (SNR) for all the aforementioned coding schemes and three small V2X-compatible data frames. Our analysis shows that turbo-based coding schemes have superior BER and FER performance than 5G coding schemes for the vast majority of the considered simulation scenarios. This fact, combined with the low-complexity requirements of turbo schemes for small data frames, makes them more suitable for small-frame 5G V2X services.